I'm not a psycologist so I'm probably wrong. But I've always seen my switches from introvert to extrovert as part of my manic depressive states. I see the unstable sense of self as Liking country music and wanting to own a farm one week then listening lots of CCR and being filled with the desire to move to a hippy commune, or wanting to be a writer who is wrapped up in the fictional world of his own making.

My likes and dislikes as well as the way I think and act all seems to change. There is no me but simply hundreds of masks that I use to face the world trying to find acceptance.